Koos van Staveren is the owner of the garage Garvak where they shot the movie. In January 2017 the movie became reality according to the news. Koos van Staveren is diagnosed with cancer and his garage is threatened by bankruptcy. Instead of running a marathon, the makers and cast of The Marathon organized a benefit evening on January 5 to raise money for Koos van Staveren. They raised almost 9500 euro for the garage.
Martin van Waardenberg was able to take time off to write this movie because of the income that he had made from appearing in a series of commercials for a famous Dutch franchise of hardware stores.
Martin van Waardenberg said that it took him 12 years to get the movie from conception to screen because the Dutch Film Foundation was reluctant to co-finance it, as they were skeptical that a movie about "four losers from Rotterdam running a marathon" would find an audience. He had to do so many concessions to get funding that he vowed to never make a movie that way again.